Various configurations of turbofan engine assemblies including internal combustion engines are known. For example, in some turbofan engine assemblies, a turbine drives the fan via a first shaft while the internal combustion engine drives the compressor(s) via a second shaft rotatable independently from the first shaft. In other configurations, the shaft of the internal combustion engine is engaged to the fan via a gearbox defining a speed reduction from the engine shaft to the fan, so that the fan rotates at a slower rotational speed than the shaft of the internal combustion engine. However, existing configurations may leave place for improvement, for example in terms of thermal efficiency and thrust specific fuel consumption of the engine assembly.